As a cable for vehicle, there is a wiring material for feeding to a stator coil of a motor, for example. Conventionally, the wiring material is manufactured by extending enamel wires wound around a stator core to a feeding section, bundling plural enamel wires, and connecting a bundle of enamel wires to the feeding section by TIG (Tungsten Inert Gas) welding or soldering.
In accordance with spread of hybrid vehicles and advance in electrification of apparatuses, higher voltage is applied to and higher current is flown in the wiring material and the motor is provided with higher output power and larger-size. Compared with the conventional device, the number of stator coils in the motor is increased, and a time required for connecting the enamel wires is increased in assembling process of the motor. Accordingly, the assembling process of the motor is required to be simplified, so that it was necessary to improve a bonding method of the enamel wire.
Thus, a technique, in which a stator coil comprising enamel wires wound around a stator core is installed in a stator housing and the enamel wires and a wiring material are connected with each other, is used (see, for example, Patent document 1 and patent document 2). For such a wiring material, there is a wiring material fabricated by punching a copper plate to have a predetermined shape (circular shape), integrally molding one set of two or three copper plates formed to have the predetermined shape by resin mold, and provide an insulation coating thereon. According to this, it is possible to reduce a space and to improve mechanization in installation of the wiring material or the like and to improve the workability in attachment.
However, in the case where the wiring material is fabricated by punching the copper plate, there is a disadvantage in that material cost becomes high due to a lot of needless parts formed by punching to have the circular shape. Further, the process becomes complicated since the step of integrally molding one set of two or three copper plates by resin mold is required. Still further, there is another disadvantage in that bad insulation occurs due to cracks in a resin mold part by a thermal fatigue due to difference in thermal expansion coefficient between a ring and the resin mold, oscillation, or the like.
Accordingly, in these days, there is a method of fabricating a wiring material by bending a linear conductor (single line conductor) coated with an insulator, in place of the method of fabricating a wiring material by punching a copper plate (For example, see Patent document 4).
When the wiring material is fabricated by this fabrication method, there is an advantage in that material cost is less expensive than the punching method in which the unnecessary parts are generated, since the linear conductor is processed by bending. In addition, there is another advantage in that electrical insulation between the linear conductors is ensured by bending the linear conductor that is previously insulation-coated, so that the step of molding the whole of the ring is unnecessary.
On the other hand, in the method of fabricating the wiring material by punching the copper plate, a feeding terminal can be also formed by punching in the process of punching in the circular shape, however, in the method of fabricating the wiring material by bending the linear conductor coated with the insulator, the feeding terminal should be prepared separately and the feeding terminal and a tip portion of the linear conductor is required to be electrically connected with each other by pressure connection.
Conventionally, when a pressure connection terminal is employed as a terminal bonding method of the single line conductor, soldering or brazing is conducted after the pressure connection, since reliability is poor when only the pressure connection is used.
In addition, as a bonding method of connecting the insulation coated conductor with a conductor terminal, a method of inserting an insulation-coated conductor into a conductor terminal, sandwiching it by a pair of electrodes to be pressured and energized is known (see Patent document 5 and Patent document 6).
Patent document 1: Japanese Patent Laid-Open No. 11-299159
Patent document 2: Japanese Patent Laid-Open No. 2001-25198
Patent document 3: Japanese Patent Laid-Open No. 2003-134724
Patent document 4: Japanese Patent Laid-Open No. 2004-96841
Patent document 5: Japanese Patent Laid-Open No. 5-114450
Patent document 6: Japanese Patent Laid-Open No. 2002-75481